Impregnation process



nited States Patent Chine 2,950,237 Patented Aug. 23, 1960IIVIPREGNATION PROCESS Filed Nov. 13, 1956, Ser. No. 621,536

Claims. or. 117-144 No Drawing.

This invention relates to a process for treating regenerated cellulosepellicular articles. More particularly, it relates to a process fordecreasing the ink-transfer and pigment-diffusing properties ofregenerated cellulose articles by controlled immersion in a bathcontaining a quaternary ammonium compound.

Regenerated cellulose articles in the form of bands, i.e., short lengthsof tubing, are well known to be useful as secondary closures for jarsand bottles. The bands usually are suitably decorated by pigmentationand/or printing. After manufacture, the bands are usually packed inliquid-tight containers together with a suitable liquid to maintain theregenerated cellulose in the gel state, for storage and/ or shipment tousers. This liquid is typically a solution containing suitablepreservatives, e.g., fungicidal and bacteriostatic compounds,rust-inhibiting agents, softeners, etc.

Among the known preservatives useful in such storage and shippingliquids are quaternary ammonium compounds, e.g., quaternary ammoniumhalides. However, it has been a disadvantage of such use of suchcompounds that, when present in the shipping liquids in suflicientamount to provide satisfactory preservative effect, e.g.,mold-resistance, undesirable printing ink-transfer and bleeding ordiffusion of pigments occurs. The transfer and bleeding occurs primarilyfrom the regenerated cellulose bands into the shipping liquid, fromwhere it readily stains other portions of the bands, but also tends tospread somewhat laterally within the bands, resulting in a hazy and lesssharp printing pattern or pigmented image.

It is therefore an object of this invention to provide a process forreducing the printing ink-transfer and pigment-diffusing tendencies ofregenerated cellulose pellicular articles in the gel state. Anotherobject is to provide such a process which permits the use of quaternaryammonium compounds as a preservative in a shipping solution withoutresultant undesirable ink transfer or pigment bleeding into the shippingsolution. A further object is to provide such a process which permitsthe use of quaternary ammonium compounds as a preservative in theshipping solution in smaller amounts than heretofore possible withoutdestroying its eifectiveness as a preservative. A still further objectis to provide such a process which is simple, economical, easilyreproducible and capable of adaption to a continuous process. Stillother objects will be apparent from the following description of theinvention.

The invention in its broadest aspects comprises the process of treatinga regenerated cellulose pellicular article in the gel state With a bathcontaining from 0.2 to 0.5% of a quaternary ammonium preservativecompound for a time sufiicient to impregnate said article with at least0.2% of said ammonium compound while maintaining the pH of said bathbetween 7 and 8. The stated percentages are by weight based on the dryweight of the regenerated cellulose article.

In one important aspect, the process of this invention comprisesimmersing a regenerated cellulose pellicular article in the gel state inan aqueous bath containing from 0.2 to 0.5% of a quaternary ammoniumhalide for a time sufficient to impregnate said article with at least0.2% of said ammonium halide while maintaining the pH of said bathbetween 7 and 8 and the temperature of said bath between and C.

In a preferred embodiment, the invention comprises the continuousprocess of dipping regenerated cellulose tubing in the gel state in anaqueous solution of 0.2 to 0.5 diisobutyl phenoxy ethoxy ethyl dimethylbenzyl ammonium chloride for a time suflicient to impregnate said tubingwith at least 0.2% of said ammonium chloride While maintaining the pH ofsaid solution between 7 and 8 and the temperature of said solutionbetween 75 and 80 C. This particular ammonium compound is preferredbecause of its outstanding regenerated cellulose preservativecharacteristics.

The treatment time required, i. e., the time sufiicient to impregnatethe regenerated cellulose article with at least 0.2% of the quaternaryammonium compound, will depend on such variables as the amount and typeof ink and/or pigments in the regenerated cellulose article, thethickness of the article, the temperature of the treating bath, thepresence of other additives in the treating bath, etc., and to a smalldegree the concentration of the ammonium compound in the treating bath.Generally, the rate of impregnation will be faster in cases where thereare less filters in the regenerated cellulose article, where the articleis thinner, where the temperature of the bath is higher and where thereare no additives in the bath. Practical treatment times for thepreferred embodiment of this invention have been found to be within therange of 20 to seconds but it is to be understood that the process ofthis invention is not limited to this range. Suitable treatment timeswill be readily determinable by persons in the art in accordance withthe teachings set forth herein.

The impregnation treatment may occur in a single immersion or in morethan one dip in the impregnation bath. It has been found advantageous totreat a regenerated cellulose article of a tubular structure in acontinuous manner by passing the flattened tubing around a series ofguide rollers, some of which are beneath the surface of a bath of thetreating solution. The tubing thus travels into and out of the bath in aseries of successive dips or immersions, for a sufiicient treatmenttime, after which the tubing may be cut into bands and packaged byprocedures well known in the art.

The treating bath must contain at least 0.2% of the quaternary ammoniumpreservative compound, based on the dry weight of the regeneratedcellulose article, in order to impregnate the article with at least 0.2%of the compound. This minimum impregnation is necessary to provide asatisfactory amount of preservative in the article. It has been found,surprisingly, that the treating bath must not contain more than about0.5% of the quaternary ammonium compound, or printing inktransfer andbleeding of pigments, which this invention avoids, will subsequentlyoccur.

It is an essential part of the process of this invention that thetreating bath be maintained at a pH between about 7 and 8. When the pHis below about 7, the quaternary ammonium preservative compound tends tolose its high bacteriostatic potency. When the pH is above about 8,subsequent ink-transfer and bleeding increases to an unacceptableamount. Control of the pH within this range may be accomplished by wellknown methods, such as the addition of suitable acidic or basiccompounds.

The impregnating bath temperature is not particular- EXAMPLE IRegenerated cellulose tubing having the gold pigmentation and coloringingredients described in Example 3 of OConnell U.S. Patent No; 2,716,614was overprinted while in the gel state as followsz Solution A g a PartsNaphthol ASG (diaceto-acetyl-o-toluidide) 12.9 Naphthol AS (anilide ofbeta-hydroxynaphthoic acid) 38.4 Monopole oil 15.0

Sodium hydroxide (20% aqueous solution) 146.0 Distilled water 181.5

The naphthol AS-G, naphthol AS and monopole oil with a little of thewater were rubbed together to form a paste. The remainder of the. waterand the sodium hydroxide were added to the paste and the mixture wasboiled for 15 minutes.

Distilled water- 17.5

The ingredients of solution B were mixed by thorough stirring.

Solution A was applied to one surface'of the regenerated cellulosetubing by means of a roll. Solution B was applied to the printing dieson a press roll, which was then rolled on the tubing. As thenaphtholated surface 'ofthe tubing passed under the inked dies, chemicalcoupling action occurred and the design penetrated into the tubing inblack. The printed tubing was then passed through wash Water to effectpurification. Excess wash water was scraped from the surface of thetubing. J

Control samples of the tubing printed as just described were cut intobands and packaged in a shipping solution which contained 1.2%diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride byweight based on the dry weight of the bands, which is the amountrequired in the shipping solution by prior art methods to obtain thedesired 0.2% preservative in the bands.

Other test samples of the tubing were impregnated with 0. preservativeby immersion for 90 seconds in an aqueous bath containing 0.3%diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride byWeight based on the dry weight of the tubing. The bath temperature washeld in the range of about 78 to 82 C. The tubing was then cut intobands and packaged in a shipping solution containing 42% glycerine, 0.6%sodium nitrite and only 0.06% diisobutyl phenoxy ethoxy ethyl dimethylbenzyl ammonium chloride (to preserve the shipping solution).

. Both the control samples and the test samples were subsequentlyexamined. Both showed no wet band mold after storage in the shippingpackage for 200 days. The shipping solutions also showed nodeterioration. The bands were then dried and both were examined after1416 hours in the dry state and showed no mold. However, control sampleswhich were examined after only 2 daysin the shipping package showed asevere amount of printingink transfer and bleeding of pigments and wereunacceptable, while test samples which were examined after 200 days inthe shipping package showed no trace of ink transfer or pigmentbleeding.

EXAMPLE II Example I was repeated except that red printing ink wasapplied using the following printing solutions:

The results were the sameas in Example I.

EXAMPLE III Example II was repeated except that the regeneratedcellulose tubing had the White opaque pigmentation and coloringingredients described in Example II of Evans U.S. Patent No. 2,141,744.Both the control samples and the test samples showed no wet band moldafter storage in the shipping package for days. The shipping solutionsalso showed no deterioration. The bands in the dry state for 1128 hoursalso showed no mold. However, control samples which were examined afteronly 2 days in the shipping package showed a very severe amount ofprinting ink transfer and bleeding of pigments and were unacceptable,while test samples which were examined after 195 days in the shippingpackage showed no trace of ink transfer or pigment bleeding.

EXAMPLE IV Example I .was repeated except that the regenerated cellulosetubing contained as pigmentation and buff coloring 14% titanium dioxide,0.225% Hausa Yellow G and 0.21% Sulfanthrene Pink FF. The Hansa Yellow Gand the Sulfanthrene Pink FF are described, respectively, at pages 634and 638 of The Chemistry of Synthetic Dyes and Pigments, edited by H. A.Lubs. and published by the Reinhold Publishing Corporation, New York,New York, '1955.

Both the control samples and the test samples showed no wet band moldafter storage in the shipping package for 119 days. The shippingsolutions also showed no deterioration. The bands in the dry state for1440 hours also showed no mold. However, control samples which wereexamined after only 1 day in the shipping package showed a very severeamount of printing ink transfer and bleeding of pigments and wereunacceptable, while test samples which were examined after 119 days inthe shipping package showed no trace of ink transfer or pigmentbleeding. EXAMPLE V Example IV was repeated except that the red printingink of Example II was used. The results were the same as in Example IV.

EXAMPLE VI atives. While the preferred compounds are halides, othercompounds which are useful include sulfates, nitrates, benzoates,hydroxides, etc. Suitable quaternary ammonium compounds are disclosed inUnited States Patents Nos. 2,087,113, 2,087,132, 2,108,765, 2,152,047and 2,295,504. The specific preferred compounds are allyl dimethylbenzyl ammonium chloride, cetyl trimethyl ammonium chloride, cetyldimethyl ethyl ammonium chloride, lauryl pyridium chloride, myristamidopropyl dimethyl benzyl ammonium chloride, octadecyl dimethyl benzylammonium bromide and particularly diisobutyl phenoxy ethoxy ethyldimethyl benzyl ammonium chloride.

The invention in its preferred form applies to the treatment ofregenerated cellulose pellicular articles obtained from viscose, but itmay also be applied to regenerated cellulose pellicular articlesobtained from cuprammonium cellulose solution, or to the treatment ofcellulose esters such as cellulose acetate, or to cellulose ethers suchas ethyl cellulose or glycol cellulose which have been cast in watersolution, or to pellicles of gelatin, casein and related substances. Bypellicular articles are meant articles formed of a pellicule, such asbands, caps, tubes, sheets, films, ribbons, etc.

In the foregoing, the invention is described in connection with thetreatment of regenerated cellulose articles in the gel state. By theterm gel is meant the state in which the regenerated cellulose articlesare obtained before any drying action has taken place.

Suitable pigments and related materials which are typically mixed in theregenerated cellulose include titanium oxide, titanium dioxide, bariumsulphate, metal flake, talc, mica, small particles of silk fibers, dyes,and other opaqueing, coloring or decorative substances. Other additives,e.g., softeners, rust inhibitors, etc., may be included in theimpregnation bath, provided of course that the pH of the bath ismaintained between 7 and 8 as described above, and provided the shippingsolution is also neutral and in equilibrium with the regeneratedcellulose gel.

The impregnation of the regenerated cellulose article according to thisinvention may take place at the same time in a continuous process as theusual purification step or it may take place in a separate step afterthe purification step. Moreover, regenerated cellulose articleswhichhave been pigmented only, or which have been printed only, mayadvantageously be impregnated as herein described.

An advantage of the invention is that it provides a new and simpleprocess for reducing the printing ink-transfer and pigment difiusingtendencies of regenerated cellulose pellicular articles in the gelstate. Another advantage is that it provides a preservative impregnatedregenerated cellulose article which can be stored or shipped in the gelstate while requiring a smaller amount of preservative in the shippingsolution. A further advantage is that it provides a simple process whichcan be used in a continuous manner to treat a moving continuous article,e.g., a continuous tube or film, with preservative, thus enabling reuseof the treating solution, a feature not possible when the preservativewas only added to the shipping solution. Still other advantages will beapparent from the above.

The invention claimed is:

1. A process for storing a pigmented regenerated cellulose pelliculararticle in the gel state which comprises first treating said articlewith a solution containing from 0.2% to 0.5% of a quaternary ammoniumhalide at a pH between 7 and 8 for a time SllffiCiGIlt to impregnatesaid article with at least 0.2%, based on the dry weight of the article,of said quaternary ammonium halide; and, thereafter, maintaining saidarticle in contact with a quaternary ammonium halide for an extendedperiod of time.

2. A process as in claim 1 wherein said solution during the firsttreating step is maintained at a temperature be tween C. and C.

3. A process as in claim 1 wherein said quaternary ammonium halide usedin the first treating step is a quaternary ammonium chloride.

4. A process as in claim 1 wherein said quaternary ammonium halide usedin the first treating step is diisobutyl phenoxy ethoxy ethyl dimethylbenzyl ammonium chloride.

5. A process as in claim 1 wherein said solution used in the firsttreating step is an aqueous solution of the quaternary ammonium halide.

References Cited in the file of this patent UNITED STATES PATENTS2,004,476 Barz et a1. June 11, 1935 2,040,061 Munz May 5, 1936 2,123,154Schirm July 5, 1938 2,432,085 Bley Dec. 9, 1947 2,680,057 Janes June 1,1954 2,741,534 Pedersen Apr. 10, 1956 UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Patent No. 2,950 2l7 August 23 1960 EllisIrving Lichtblau It is hereby certified that error appears inthe-printed specification of the above numbered patent requiringcorrection and that the said Letters Patent should read as correctedbelow.

Column 2, line 30, for "filters" read fillers column 5, line 5, for"2,08%113" read 2,087,131

Signed and sealed this 4th day of April 1961 (SEAL) Attest: ERNEST W.SWIDER XXXXXXX ARTHUR W. CROCKER Attesting ()fiicer Acting Commissionerof Patents

1. A PROCESS FOR STORING A PIGMENT REGENERATED CELLULOSE PELLICULARARTICLE IN THE GEL STATE WHICH COMPRISES FIRST TREATING SAID ARTICLEWITH A SOLUTION CONTAINING FROM 0.2% TO 0.5% OF A QUATERNARY AMMONIUMHALIDE AT A PH BETWEEN 7 AND 8 FOR A TIME SUFFICENT TO IMPREGNATE SAIDARTICLE WITH AT LEAST 0.2% BASED ON THE DRY WEIGHT OF THE ARTICLE, OFSAID QUATERNARY AMMONIUM HALIED, AND, THEREAFTER, MAINTAINING SAIDARTICLE IN CONTACT WITH A QUATERNARY AMMONIUM HALIDE FOR AN EXTENDEDPERIOD OF TIME.